Method osi treating rubber articles



E. c. TAYLOR. METHOD' OF TREATING RUBBER ARTICLES.

APPLICATION FILED OCT. 7. 1920.

Patented July 11, 1922;

6 m i mw w 2 R W 0 0 M Z 2 o o o 4. w A." Q. m )1 AU V to flow without displaci the carcass the mold sections may be safe y closed and the desired molding pressure applied. The tire is now ready tor vulcanization, which may be carried out in any desired way usually p the molds used for formi by filling with steam the chamber in which the molds are placed. In cases where a cool ing medium has been circulated through the core on which the casing is mounted it may be found desirable to replace the cooling medium with a heating medium to bring the tire to an even temperature, and the heat supplied to the core in this instance may be maintained durin vulcanization or discontinued as desired In or der to disclose more particularly one manner in which my invention may be practiced I will now refer to the accompanying drawings, in which-- Fig. 1 is a section of a tire casing, showing} by stippling the warmer area;

V ig. 2 is a similar view showing the complete y cured casing; and

Fig. 3 is a cross-sectional elevation, partly broken away, of a vulcanizing chamber with associated parts showin an arrangement whereby the inside of e casings may be maintained at a lower temperature than the outside. Y

A tire casing 10 in its unvulcanized state is, in this manner of practicing in invention, mounted on a core 11 arran ed to permit of its bein maintained at :1 wer temperature than t at of its surroundings. As shown, the core is hollow, aflording a space 12 for the circulation of a cooling medium.

The heater may be generally of the usual construction, having a body portion 13 provided with a removable cover 14 and a hydraulic ram 15 serving to press articles mounted thereon against the cover. Provision is made, as by an inlet 16 and an outlet ].7, for circulating a heating medium through the interior of the heater around the articles mounted on theram. I have shown the tire casings durin vulcanization as bei of the usual type, having two mating sections 1.8 and 19 which form between them a molding recess of the shape of the tire. In order to circulate a cooling medium through the hollow cores on which the casings are mounted I have shown a pipe 20 connected by a flexible pipe 21 with the uppermost core flexible ipes 22 joining adjacent cores, and a pipe 3 joining the lowermost core to the outlet. The hollow interior of the core may be joined to the piping described by suitable connections not necessary to illustrate.

Toggle operated double wedges 24 are provided which serve to hold the mold sections apart and to hold they care and the tire mounted thereon in acentral position with respect to the .mold sections, as is clearly shown in the lowermost mold in Fig. 3. The

inner ends of the toggles 25 are pivoted to heads 26 having flanges arranged to hold the toggles in rative position, the Line of the 'vots on eads 26- being in this position s ightly lower than the outer ends of the toggle arms. A head 27, controlled by lever System28 firom pawls 29 serves to raise the lowermost head 26 when by the elevation of ram 15 pawls 29 are tripped by lugs 30 secured to the heater.

In practicing my invention with the above device the tire casings, supported on the hollow cores, are arranged within the mold sections with wedges 24 in position and the ipin connected. -The cover 14' is ap lied, a coo mg medium, such as water, circu ated through the cores, and a heatin medium, such as steam, admitted to the interior of the heater. After the tread has become softened relative to the carcass the supply of the cooling medium is discontinued, and, if desired, replaced b a heating medium, and the ram 15 elevate This first trips the pawl and lever mechanism described above and then applies pressure to the molds by pressing them against the cover of the heater. The tread bei softened by heat Sillustrated by the stipplmg in Fig, 1) whi e the carcass remains in its normal condition or is stiffened by being cooled, the molding of the tread into the desired form as indicated by 31, Fig. 2, is accomplished without injury to the carcass.

It is not necessary in carrying out my invention to use the apparatus just described. For example the cores may be chilled, leaving the tread portion at substantially atmospheric temperature, and the cores and casings then placed in molds and pressure applied in the usual way but before the temperature of the casing has had time to equalize. Or the core may be cooled and the tread warmed before placing'the' casing in the mold in the usual way. Or a short heat maybe given the tread while relying on the high specific heat of the core to keep the carcass temperature lower than the tread, care being taken not to continue the heating to a point where the carcass commences to soften. Or the casings may be assembled in molds in a heater in the usual manner but without applying pressure to the casings until the difference in the resistances to flow has been increased by cooling the core or heating the tread. In the latter case the weight of the molds alone will notbe sufiicient to cause shifting of the carcass unless too many are piled upon each other. In all these cases it -is desirable in practicing my invention to discontinue the preliminary heating, if given, before substantial vulcanization takes place, as after this point is reached the heat serves to stiffen the rubber instead of softening it. In short, I realize that my invention may be practiced in numerous ways, some of which I have pointed out, and do not wish it to be limited in scope except as defined in the appended claims.

I claim:

1. The method of vulcanizing an assembled tire casing comprising locating the casing on a hollow core, directing a cooling medium into the interior of the core, subjecting the exterior of the casing to heat, and subsequently applying molding pressure and vulcanizing heat to the casing.

2. In the vucanization of tire casings, assembling the carcass and tread portions upon a hollow core, introducing a cooling medium into the core, subjecting the ex terior of the casing to heat to warm and soften the tread relative to the carcass, hold ing the casing under molding pressure while the tread is warmer than the carcass, and subsequently vulcanizing the casing.

3. In the vulcanization of tire casings, assembling the carcass and tread portions upon a hollow core, introducing a cooling medium into the core, subjecting the outside of the casing to heat to warm and soften the tread relative to the carcass, holding the casing under molding pressure between the core and an outer rigid mold while the tread is rigid mold.

EDWARD C. TAYLOR. 

